how to fix P0420 code on my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the engine is cool.
• Disconnect the negative battery terminal to prevent electrical issues.

2. Inspect and Replace Oxygen Sensors

• Tools Required: O2 sensor socket, ratchet, torque wrench
• Remove the upstream oxygen sensor:
  1. Locate the upstream O2 sensor near the exhaust manifold.
  2. Use the O2 sensor socket to carefully unscrew the sensor.
  3. Install the new sensor by threading it in by hand, then torque it to manufacturer specifications (typically around 30 lb-ft).
• Remove the downstream oxygen sensor:
  1. Locate the downstream O2 sensor near the catalytic converter.
  2. Repeat the process of removal and installation as above.

3. Inspect and Replace Catalytic Converter (if necessary)

• Parts Required: New catalytic converter
• Tools Required: Socket set, jack and jack stands, exhaust pipe cutter (if applicable), new exhaust gaskets
• To remove the catalytic converter:
  1. Raise the vehicle using a jack and secure it with jack stands.
  2. Disconnect the exhaust pipes from the catalytic converter using a socket set.
  3. Remove any mounting brackets or heat shields.
  4. If necessary, use an exhaust pipe cutter to cut the old catalytic converter out.
  5. Install the new catalytic converter, ensuring proper alignment and sealing with new gaskets.
  6. Reattach all exhaust components and ensure they are secured correctly.

4. Reset the Engine Control Module (ECM)

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to clear the P0420 code from the ECM.